Chair

Abstract: In a chair comprising a seat portion (3) which is suspended through two swingable links (4, 5) to be swingable with respect to a base portion (2) comprising a leg portion (6, 7) and a seat holder (12), the distance between lower ends of the two links (4, 5) is rendered changeable so that the parallelism between the two links (4, 5) can be changed thereby varying a swinging mode of the seat portion (3). Thus, lower ends of the two links (4, 5) are brought into engagement with two sliders (21, 22) which are guided to be operable in directions for approaching to/separating from each other respectively.

Description: The present invention relates to a chair, and more particularly, it relates to a chair comprising a swingable seat portion. Japanese Utility Model Publication No. 2-35251 (1990) describes a chair, which is suitable for seating an infant, provided with a seat portion which is swingable with respect to a base portion having a leg portion. Briefly stated, the seat portion of this chair is suspended with respect to the base through two swingable links. The two links are arranged in parallel with each other, whereby the seat portion swings while keeping its horizontal state. On the other hand, Japanese Utility Model Publication No. 5-6847 (1993) also described a chair for an infant comprising a seat portion which is suspended with respect to a base portion through two swingable links in a swingable manner. In this chair, the two links are not parallel to each other but the distance between lower ends thereof are made longer than that between upper ends. Upon swinging, therefore, the seat portion rocks the infant for alternately vertically moving its head and feet without keeping its horizontal state. When the seat portions swing in the aforementioned manners, the two types of typical movements have advantages of their own. The swinging movement of the former seat portion keeping its horizontal state is suitable for putting an infant to sleep immediately after suckling it, for example, since this movement is rather unstimulative. On the other hand, the swinging movement of the latter seat portion rocking the infant is similar to and hence substitutable for the movement of a mother rocking her baby to sleep in her arms. Thus, it is preferable to vary the mode of a swinging movement for an infant with the situation. Accordingly, an object of the present invention is to provide a chair which can vary its swinging mode at need. US-A-165.0178 cited in the search report for this application discloses a swinging davenport chair comprising a base portion having a leg portion; a seat portion; and four chain links suspending the seat portion from the base portion for rendering the seat portion swingable with respect to the base portion in a swinging direction, the four chain links comprising two chain links spaced apart in the swinging direction of seat portion on respective opposite sides of the seat portion, with the spacing apart of the upper and lower ends of the chain links on each side of the seat portion being separately changeable whereby the degree of parallelism between the chain links on each side of the seat portion is separately changeable. In accordance with the present invention there is provided a chair comprising: a base portion having a leg portion; a seat portion; and two swingable links for suspending said seat portion from said base portion for rendering said seat portion swingable with respect to said base portion in a swinging direction, each link being substantially U-shaped with a base which is positioned under said seat portion and two arms which extend upwardly from said base on respective opposite sides of said seat portion, said bases of said substantially U-shaped links being spaced apart in the swinging direction of said seat portion; and said chair being provided with means for changing the spacing apart of said bases for changing the degree of parallelism between the arms of said links symmetrically on each of said opposite sides of said seat portion. Preferably, the base of each substantially U-shaped link is attached to a respective slider which is movable in the swinging direction. Advantageously the sliders are provided with respective grooves for receiving said links. The means for changing the spacing apart of the bases of the links in the chair defined in the last but two paragraph may include two sliders operably guided towards and away from each other, each slider being engaged with a respective base and an interlocking mechanism for symmetrically driving said two sliders with each other. The above-mentioned interlocking mechanism may include cross bars rotatably supported with respect to said seat portion and arranged in an X shape, said cross bars each having one end being operably coupled to one said slider and the other end being operably coupled to the other said slider respectively. Each operable coupling between said crossbars and sliders may comprise a pin on an end portion of one of said crossbars engaged in a slot in one of said sliders. One of said sliders may be provided with an operating part which is engageable with an operator's hand. Alternatively, the interlocking mechanism may include a rotor rotatably mounted with respect to said seat portion, and a respective coupling bar operably coupling each of said sliders with said rotor, said coupling bars being connected to said rotor at diametrically opposite locations thereon. The rotor may be provided with a rib for enabling an operator to readily rotate the same. Preferably, the chair further includes elastic engaging means for stably maintaining said sliders in end positions of operations thereof. The elastic engaging means may include a combination of a plate spring and an engaging wall for elastically engaging with the same. According to the present invention, therefore, it is possible to selectively implement a swinging mode of the seat portion keeping its horizontal state and another swinging mode accompanied by a rocking movement in a single chair. Thus, it is possible to provide proper modes of swinging movements for an infant in response to its situations. It is to be noted that the aforementioned different modes of swinging movements can be implemented in a single chair. Thus, it is not necessary to provide a plurality of chairs in response to the situations. Further, in the embodiments described hereinafter, the modes of the swinging movements can be selected while seating the infant on the chair with no requirement for moving it to another chair. In order that the invention may be melt understood two embodiments thereof, which are given by way of example only melt now be described with reference to the accompanying drawings, in which: Fig. 1 is a side elevational view showing the appearance of a chair 1 according to a first embodiment of the present invention; Fig. 2 is an enlarged view showing an essential part of the chair 1 as viewed along arrow II in Fig. 1 in a partially fragmented manner; Fig. 3 is a partially fragmented side elevational view illustrating a seat portion 3 in a state capable of providing a first swinging mode which is implemented in the chair 1 shown in Fig. 1; Fig. 4 is a side elevational view illustrating links 4 and 5 in the state shown in Fig. 3; Fig. 5 is a plan view illustrating sliders 21 and 22 in the state shown in Fig. 4; Fig. 6 is an enlarged side elevational view illustrating a plate spring 39 and an engaging wall 40 in the state shown in Fig. 4; Fig. 7 is a partially fragmented side elevational view illustrating the seat portion 3 in a state capable of providing a second swinging mode which is implemented in the chair 1 shown in Fig. 1; Fig. 8 is a side elevational view illustrating the links 4 and 5 in the state shown in Fig. 7; Fig. 9 is a plan view illustrating the sliders 21 and 22 in the state shown in Fig. 8; Fig. 10 is an enlarged side elevational view illustrating the plate spring 39 and the engaging wall 40 in the state shown in Fig. 8; Fig. 11 is a side elevational view corresponding to Fig. 4, for illustrating another embodiment of the present invention; Fig. 12 is a plan view corresponding to Fig. 5, for illustrating the embodiment shown in Fig. 11; Fig. 13 is a side elevational view corresponding to Fig. 8, for illustrating the embodiment shown in Fig. 11; and Fig. 14 is a plan view corresponding to Fig. 9, for illustrating the embodiment shown in Fig. 11. Referring to Fig. 1, the chair 1 generally comprises a base portion 2 and a seat portion 3. The seat portion 3 is swingably suspended with respect to the base portion 2 through two swingable links 4 and 5. The base portion 2 comprises front legs 6 and rear legs 7 forming a leg portion. The front and rear legs 6 and 7 cross each other and are coupled with each other by a pivot portion 8 at the crosspoint. Front wheels 9 and rear wheels 10 are rotatably mounted on lower end portions of the front and rear legs 6 and 7 respectively, so that it is possible to move the overall chair 1 through the front and rear wheels 9 and 10 rolling on a floor face 11. In relation to the front wheels 9, for example, a brake mechanism (not shown) may be further provided for selectively inhibiting their rotation. Seat holders 12 are mounted on respective upper end portions of the front and rear legs 6 and 7. In more concrete terms, the front and rear legs 6 and 7 are rotatably mounted on the seat holders 12 through pivot portions 13 and 14 respectively. The pivot portions 14 are positioned on movable portions 15 which are provided in the respective seat holders 12. The position of the movable portions 15 can be controlled back and forth along the chair 1, whereby the angle between the front and rear legs 6 and 7 can be changed for adjusting the height of the seat portion 3 as the result. A mechanism for changing the position of the movable portions 15 is not directly related to the subject matter of the present invention, and hence detailed description thereof is omitted. On the other hand, the seat portion 3 comprises a seat 16, a backrest 17, side walls 18 uprightly provided on both sides of the seat 16, a footrest 19, and a table 20. The backrest 17 is preferably reclinable. Further, the table 20 is detachable. As clearly shown in Fig. 2, each side wall 18 has an inverted U-shaped section, so that the seat holder 12 is partially located in the side wall 18. Each of the links 4 and 5 is a rod and as clearly shown in Fig. 2 with respect to the link 5 is substantially U-shaped with a base, or lower end, which is positioned under the seat portion 3 and two arms which extend upwardly from the base of the link on respective opposite sides of the seat portion. Upper end portions of the arms of the links 4 and 5 are rotatably mounted on the respective seat holder 12 at fixed points and the bases of the substantially U-shaped links 4, 5 are spaced apart in the swinging direction of the seat portion 3. Comparing Figs. 3 and 7 showing states for providing different operating modes respectively, it is understood that the spacing apart of the bases, or lower ends, of the links 4 and 5 is changeable for changing the degree of parallelism between the arms of the links symmetrically on each of the opposite sides of the seat portion. As shown in Figs. 4 and 5 and Figs. 8 and 9 respectively, portions cross-directionally extending along the chair 1 for forming the bases, or lower ends, of the links 4 and 5 engage with sliders 21 and 22, which are paired with each other, respectively. The sliders 21 and 22 are provided with grooves 23 and 24 for receiving the links 4 and 5 respectively. These sliders 21 and 22 are guided to be movable towards and away from each other in the swinging direct within a prescribed range, by guides 25 shown by one-dot chain lines in Figs. 5 and 9. These guides 25 are provided on a lower surface of the seat 16. The slider 22 is provided with an operating part 26, which can engage with the fingers of an operator. This operating part 26 is moved back and forth to drive the slider 22 back and forth, thereby symmetrically driving the other slider 21 back and forth in association with this operation, as understood from Figs. 4 and 5 and Figs. 8 and 9 in comparison. Such an interlocking mechanism is now described. Figs. 4 and 8 show a boss 27 which extends from the lower surface of the seat 16. A pin 28 is mounted on the boss 27, for rotatably supporting cross bars 29 and 30 which are arranged in an X shape respectively. Pins 31 and 32 are provided on respective end portions of the cross bar 29, to be received in slots 33 and 34 which are provided in the sliders 21 and 22 respectively. On the other hand, pins 35 and 36 are also provided on respective end portions of the cross bar 30, to be received in slots 37 and 38 which are provided in the sliders 22 and 21 respectively. When the slider 22 is driven back and forth in response to the operation of the operating part 26, therefore, the other slider 21 is also driven back and forth in a symmetrical manner through the cross bars 29 and 30. Thus, the distance between the bases, or lower ends, of the links 4 and 5 can be changed about the pin 28. The sliders 21 and 22 are preferably stably kept in end positions of the operations thereof. Therefore, plate springs 39 are mounted on the slider 21, while engaging walls 40 are formed to extend from the lower surface of the seat 16. Figs. 6 and 10 show the relation between each spring 39 and each engaging wall 40 in an enlarged manner. The plate spring 39 is provided with a bulge portion 41, while the engaging wall 40 is provided with two engaging cavities 42 and 43. In the state shown in Figs. 3 to 6, the bulge portion 41 of each plate spring 39 engages with the engaging cavity 42 of each engaging wall 40, and is stably kept in this state. In the state shown in Figs. 7 to 10, on the other hand, the bulge portion 41 engages with the other engaging cavity 43, and is stably kept in this state. When relatively strong force is applied to the operating part 26 to drive the sliders 21 and 22, the bulge portion 42 can readily disengage from the engaging cavity 42 or 43. Under the aforementioned structure, the state shown in Figs. 3 to 6 is implemented as follows: Namely, this state is implemented when the operating part 26 is pulled back from the chair 1. Thus, the sliders 22 and 21 are rearwardly and frontwardly moved respectively. The bulge portion 41 engages with the engaging cavity 42, for stably keeping this state. The distance between the lower ends of the links 4 and 5 is maximized upon such operations of the sliders 21 and 22 as hereinabove described, whereby this distance is rendered longer than that between the upper ends. Consequently, a swinging movement accompanied by rocking is implemented as shown by solid and phantom lines in Fig. 3. In order to attain the state shown in Figs. 7 to 10, on the other hand, the operating part 26 is pushed frontwardly along the chair 1. Thus, the sliders 22 and 21 are frontwardly and rearwardly moved respectively. The bulge portion 41 engages with the engaging cavity 43, thereby stably keeping this state. The distance between the lower ends of the links 4 and 5 is minimized upon such operations of the sliders 21 and 22 as hereinabove described, whereby this distance is rendered equal to that between the upper ends for parallelizing the links 4 and 5. Consequently, the seat portion 3 swings while keeping a horizontal state, as shown by solid and phantom lines in Fig. 7. Figs. 11 to 14 are adapted to illustrate another embodiment of the present invention. Figs. 11, 12, 13 and 14 correspond to Figs. 4, 5, 8 and 9 respectively. Referring to Figs. 11 to 14, elements corresponding to those shown in Figs. 4, 5, 8 and 9 are denoted by similar reference numerals, to omit redundant description. The embodiment shown in Figs. 11 to 14 is provided with rotors 44 and coupling bars 45 and 46 in order to interlock sliders 21 and 22 with each other, and comprises no elements corresponding to the aforementioned cross bars 29 and 30 and the operating part 26. The rotors 44, which are arranged on both sides of a chair 1 respectively, are coupled with each other by a synchronous bar 47, and held by this synchronous bar 47 to be rotatable with respect to a seat portion 3. The rotors 44 are provided with ribs 48 for facilitating rotations thereof. First ends of the coupling bars 45 and 46 are coupled with the rotors 44 at diametrically opposite locations thereon through pins 49 and 50 respectively. On the other hand, second ends of the coupling bars 45 and 46 are rotatably coupled to sliders 21 and 22 through pins 51 and 52 respectively. When the pins 51, 49, 50 and 52 are aligned with each other as shown in Figs. 11 and 12, therefore, the sliders 21 and 22 most separate from each other to maximize the distance between lower ends of links 4 and 5. Consequently, a state which is substantially similar to that shown in Fig. 3 is implemented so that the seat portion 3 swings with a rocking movement. When the rotors 44 are rotated by 90° from the state shown in Figs. 11 and 12 as shown in Figs. 13 and 14, on the other hand, the sliders 21 and 22 are moved by the coupling bars 45 and 46 to approach to each other. Thus, the distance between lower ends of the links 4 and 5 is minimized so that this distance is equal to that between the upper ends, thereby parallelizing the links 4 and 5 with each other. Consequently, a state which is substantially identical to that shown in Fig. 7 is attained so that the seat portion 3 swings while keeping its horizontal state. While the present invention has been described with reference to the embodiments shown in the drawings, some modifications are also available with the scope of the appended claims. While the degree of parallelism between the links 4 and 5 can be adjusted to two states in each of the aforementioned embodiments, the same may be adjusted to three or more states, or rendered continuously adjustable in a stepless manner, for example. While the distance between the lower ends, or bases, of the links 4 and 5 is changed in each of the aforementioned embodiments for changing the parallelism between the two links 4 and 5, both of the distances between the upper and lower ends may alternatively be changed. Further, the parallelism between the two links 4 and 5 may be changed by a structure other than those shown in Figs. 1 to 10 and Figs. 11 to 14. The chair is preferably provided with a mechanism for selectively inhibiting a swinging movement of the seat portion, although such a mechanism is not particularly described in relation to the aforementioned embodiments. While each of the aforementioned chairs 1 is prepared for an infant, the present invention is not restricted to such a chair for an infant but to a chair for an adult, for example. While the seat portion 3 is swingable back and forth with respect to the base portion 2 in each of the aforementioned embodiments, the present invention is also advantageously applicable to a seat portion which is swingable from side to side.

Claims: A chair, comprising: a base portion (2) having a leg portion (6, 7); a seat portion (3); and two swingable links (4, 5) for suspending said seat portion (3) from said base portion (2) for rendering said seat portion (3) swingable with respect to said base portion (2) in a swinging direction, each link (4, 5) being substantially U-shaped with a base which is positioned under said seat portion (3) and two arms which extend upwardly from said base on respective opposite sides of said seat portion, said bases of said substantially U-shaped links (4, 5) being spaced apart in the swinging direction of said seat portion (3); and said chair being provided with means for changing the spacing apart of said bases for changing the degree of parallelism between the arms of said links (4, 5) symmetrically on each of said opposite sides of said seat portion (3). A chair according to claim 1 wherein the base of each substantially U-shaped link (4, 5) is attached to a respective slider (21, 22) which is movable in the swinging direction. A chair according to claim 2, wherein said sliders (21, 22) are provided with respective grooves (23, 24) for receiving said links (4, 5). A chair according to any one of claims 1 to 3, wherein said base portion (2) includes a wheel (9, 10) rollable on a floor face (11). A chair according to any one of claims 1 to 4, wherein said leg portion includes a front leg (6) and a rear leg (7) crossing each other and coupled rotatably with each other at a crossing point thereof, said seat portion (3) having a variable height by altering the angle between said front leg (6) and said rear leg (7). A chair according to claim 1, wherein said means for changing the spacing apart of said bases of said links (4, 5) includes two sliders (21, 22) operably guided towards and away from each other, each slider being engaged with a respective base and an interlocking mechanism (29, 30, 44, 45, 46) for symmetrically driving said two sliders (21, 22) with each other. A chair according to claim 6, wherein said interlocking mechanism (29, 30, 44, 45, 46) includes cross bars (29, 30) rotatably supported with respect to said seat portion (3) and arranged in an X shape, said cross bars (29, 30) each having one end being operably coupled to one said slider (21) and the other end being operably coupled to the other said slider (22) respectively. A chair according to claim 7, wherein each operable coupling between said crossbars (29, 30) and sliders (21, 22) comprises a pin (31, 32, 35, 36) on an end portion of one of said crossbars engaged in a slot (33, 34, 37, 38) in one of said sliders. A chair according to claim 7 or 8, wherein one of said sliders (22) is provided with an operating part (26) which is engageable with an operator's hand. A chair according to claim 6, wherein said interlocking mechanism (29, 30, 44, 45, 46) includes a rotor (44) rotatably mounted with respect to said seat portion (3), and a respective coupling bar (45, 46) operably coupling each of said sliders (21, 22) with said rotor, said coupling bars being connected to said rotor at diametrically opposite locations thereon. A chair according to claim 10, wherein said rotor (44) is provided with a rib (48) for enabling an operator to readily rotate the same. A chair according to any one of claims 6 to 11, further comprising elastic engaging means (39, 40) for stably maintaining said sliders in end positions of operations thereof. A chair according to claim 12, wherein said elastic engaging means includes a combination of a plate spring (39) and an engaging wall (40) for elastically engaging with the same.

Inventors: KASSAI KENZOU, YONEDA YOSHIFUMI, KASSAI, KENZOU, YONEDA, YOSHIFUMI, YONEDA, YOSHIFUMI, C/O APRICA KASSAI K.K.
Applicants: APRICA KASSAI KK, APRICA KASSAI KABUSHIKIKAISHA
Application year: 1994
Main classification: A47D13
IPC codes: A47D13, B62B9, A47D1, A47C3